Integumentary System - AnaPhy Lab Flashcards
The integumentary system is composed of
skin, or cutaneous membrane, plus its accessory structures: hairs, nails, and glands.
the largest and most visible organ of the body
skin
functions of skin
- protection by forming an impenetrable barrier to infectious agents
- excretion of sweat, waste products (including lactic acid and urea) are released onto the skin.
- enable sensations, such as touch, pain, temperature, pressure, and vibration
- thermoregulation by removing excess heat or preventing heat loss
- synthesis of vitamin D
The skin is made up of two distinct layers:
the superficial epidermis and the underlying dermis
lies deep to the dermis, and although it is not considered a component of the skin, it does help the skin perform its functions
hypodermis (or subcutaneous layer)
consists of loose connective tissue with many blood vessels and adipose tissue.
hypodermis
The epidermis is
avascular and composed of keratinized, stratified squamous epithelium
The epidermis contains four distinct cell types:
keratinocytes, melanocytes, dendritic (Langerhans) cells, and Merkel (tactile) cells
produce the strong waterproofing protein keratin
keratinocytes
produce the protective pigment melanin
melanocytes
are specialized white blood cells that migrate to the epidermis, where they function as phagocytes.
dendritic (Langerhans) cells
are located at the epidermal–dermal junction and function in light touch reception
Merkel (tactile) cells
thick skin is located where
only in the palms of the hands and the soles of the feet
thick skin contains how many strata?
five strata
thin skin is located where
located everywhere else in the body
thin skin contains how many strata?
four strata
what stratum is absent in thin skin?
stratum lucidum is absent
what are the five layers/strata of the epidermis? (from top to bottom)
Stratum corneum
Stratum lucidum
Stratum granulosum
Stratum spinosum
Stratum basale
the deepest layer of the epidermis, consists of a single layer of cuboidal epithelial cells (keratinocytes) attached to a basement membrane.
stratum basale
contains 8–10 layers of cells, mostly keratinocytes that have a “spiny” appearance in histological preparations.
stratum spinosum
consists of three to five layers of keratinocytes that undergo a drastic change in appearance as they begin to fill with keratin (a process called keratinization).
stratum granulosum
which is found only in the thick skin of the palms and soles, consists of two to four translucent layers of flat, dead keratinocytes
stratum lucidum
The most superficial epidermal stratum, the ______________________, is the thickest stratum, consisting of 20–30 layers of cells.
stratum corneum
Underlying the epidermis is the highly vascular ______
dermis
Underlying the epidermis is the highly vascular dermis,
which consists of a
papillary layer and a reticular layer
which lies immediately deep to the stratum basale and largely consists of loose connective tissue, is so named because it contains finger-like
projections called dermal papillae, many of which contain
capillary loops that provide a blood supply to the overlying,
avascular epidermis
papillary layer
finger-like projections called ___________________ , many of which contain capillary loops that provide a blood supply to the overlying, avascular epidermis.
dermal papillae
Other dermal papillae contain __________________, which respond to light touch, or free nerve endings, which function as pain or temperature receptors.
tactile (Meissner) corpuscles
are prominent on the hands and feet and form dermal ridges that indent the epidermis and form fingerprints.
Dermal papillae
the deepest layer of the skin, consists largely of dense, irregular connective tissue and accounts for approximately 80% of dermal thickness.
reticular layer
The reticular layer contains
an abundance of collagen fibers (for strength), elastic fibers (for flexibility), and reticular fibers (to form a supporting network for dermal structures).
are also located in the reticular layer. Their multilayered capsule is specialized to detect pressure and vibrations
Lamellated (Pacinian) corpuscles
The accessory structures of the skin include
hairs, nails, and glands
Hairs are found all over the body surface—with the exception of the
palms, soles, lips, parts of the external genitalia,
and nipples.
are produced by structures called hair follicles
Hairs
Hairs are produced by structures called
hair follicles
Hairs consist of two basic parts:
shaft and root
which is composed of dead, keratinized epithelial cells and projects from the skin surface
hair shaft
which is enclosed by the hair follicle projecting down into the dermis
hair root
a hair can be seen to consist of three distinct layers of keratinized cells
an inner medulla, a middle cortex, and an outer cuticle
Hair color is largely determined by the type and amount of ________ within the _______________
melanin; cortex
is formed by layers of epidermal tissue, called the epithelial root sheath, that is surrounded by a dermal root sheath composed of connective tissue.
hair follicle
layers of epidermal tissue that is surrounded by a dermal root sheath composed of connective tissue
epithelial root sheath
cause goosebumps
arrector pili muscle
knob-like base of the hair root that contains the matrix, the living, mitotically active part of the hair that adds new hair cells to the base of the hair root.
hair bulb
are connected to the base of the hair bulb
sensory receptors
a small projection of dermal tissue from the dermal root
sheath that protrudes into the hair bulb, contains capillaries
that supply the growing hair cells with oxygen and nutrients
hair papilla
are modifications of the epidermis that protect the dorsal ends of the fingers and toes.
Nails
These structures are associated with a nail:
two nail folds, the eponychium (or cuticle), lunula
the folds of skin along either side of the nail body
two nail folds
the thick fold at the proximal end of the nail
eponychium (or cuticle)
the white, crescent-shaped region at the base of the nail.
lunula
rests on a region of the epidermis called the nail bed.
nail body
nail body rests on a region of the epidermis called the
nail bed
The thickened proximal portion of the nail bed, called the _______________, is responsible for nail growth
nail matrix
are exocrine glands—glands that release
their secretory products onto external or internal body surfaces.
Sebaceous Glands
Most sebaceous glands secrete an oily, acidic substance called _____________ into hair follicles, although some deposit sebum directly onto the skin surface.
sebum
acts as a lubricant that keeps the skin and hair soft and moist and deters the growth of infectious agents
sebum
Sebaceous glands are located
in skin everywhere except the palms and soles.
which are also exocrine glands, consist of a coiled secretory component and a duct composed of simple cuboidal epithelial tissue.
sweat glands
Two types of glands produce sweat:
eccrine sweat glands and apocrine sweat glands
are distributed all over the body, and they secrete sweat that is primarily water but also contains salts and waste products.
eccrine sweat glands
The primary function of eccrine sweat glands is
temperature regulation
are confined to the groin, axillae, and the areola around each nipple.
apocrine sweat glands
They tend to be larger and deeper in the dermis than eccrine sweat glands, and they have ducts that empty into hair follicles
apocrine sweat glands
